Sonny Bill Williams says he'll have to be at his best to make New Zealand's Rio Olympics rugby sevens squad.
The lure of Olympic gold - to go along with a Rugby World Cup and two NRL premierships - has tempted Williams away from Super Rugby after he was named on Wednesday in an initial 16-strong squad for next year's world series and Rio Games.
"Going back in time, the best sportsmen ever have been Olympians - (Usain) Bolt, (Muhammad) Ali," Williams said.
"It's just an awesome opportunity to try and achieve that."
Williams is joined by All Blacks and Chiefs teammate Liam Messam in the squad, making them unavailable for Super Rugby next year.
"To be good at this game, you've got to be training it and playing it," coach Sir Gordon Tietjens said.
He said Williams had shown how easily he could adapt to the demands of rugby after making the switch from rugby league.
"I see him adjusting very well to the fast pace of sevens. He'll be a great attacking weapon with his speed, strength and uncanny ability to offload."
Although Williams hasn't played sevens rugby, he'll have ample opportunity to prove himself.
"He's a real professional athlete, and he's certainly got all the skill sets to be a very, very good sevens player," Tietjens said.
"He's never played sevens but Sonny will be involved in six world series tournaments to demonstrate that he could be worthy of going to Rio."
Williams himself has no illusions about the work he needs to if he wants to get up to speed in the sevens game.
"It's going to be a massive challenge, probably the biggest of my career, but I'm definitely going to give it my all.
"I don't know if I'm going to be any good at sevens, that's why it's pretty scary. But I'm sure as hell going to try my hardest."
Committing to sevens rugby fulltime meant no Super Rugby next year, but Williams said that was a logical move to make.
"I've committed to doing sevens fulltime - obviously the other players have had sevens experience and I've had nothing.
"Going into such a big campaign, for me to put my best foot forward, I know that's the only way to get as much experience as I can."
Although the initial squad will form the basis of teams to be selected for the world series and the Rio Olympics, Tietjens said there was the option to add further contracted players later this year.